Why is no one mentioning Radiant Strike? Its at will, people. At will.
Here's how our cleric rolled at level 1.
2/encounter, healing word, heals surge+1d6+4.
1/day, beacon of hope, heals 9 in a radius, improves healing word (you were adding your wisdom modifier to the healing from beacon of hope, right? its a clerical healing power)
at will, radiant strike- at level 1, it added two temporary hit points every time the cleric succeeded on an attack. This essentially reduces damage by two the next time an enemy hits. Its functionally equivalent to healing if you target your allies wisely. This may seem small, but its at will and it really adds up. And it improves rapidly as you level, eventually becoming really, really effective.
in emergencies, heal checks- they put people back on their feet when their down and you need to trigger their second wind
So, OP- how many people are in your group? If its 5, including the cleric, you should be doing alright. Remember, part of the responsibility for healing is on the individual in 4e. Everyone has Second Wind, and they should be using it. Also make sure that the rest of your group is playing wisely. Its possible that you don't feel like you have enough healing because your group is too reckless. Look and see if the defender characters are protecting the strikers, and so forth.
Finally, the most common reason that groups find themselves lacking enough healing is that they don't have enough melee combatants. How many of your groups total characters fight in melee? If its only two out of five or so, you may have a problem simply because those two characters can't take the punishment, and can't stop enemies from slipping past them.